Tuesday, August 18, 2015

It Begins

Finally.  Working on the actual hardtop.  Can't believe how much work has been put into this project just to get to the starting point.  Building a workshop, a work table, a frame mold, a fiberglass roll holder/table, trying to make the workshop a bit more weatherproof and other improvements took a long time. But now we are making a little progress toward actually creating the top.

It started with dragging two panels of foam to the work site,  One was the piece I cut the test panel from and I used it to cut another 15 inch section off of the end. Then we started poking holes in the face of that piece and the full 4 foot by 8 foot section.  The hole poking tool that we started with had 36 nails in it and we quickly decided it was difficult to work.  Those 36 nails, when pushed into the foam, hold on pretty well and you really have to pry it back off.  So, the tool was reduced to just 9 nails and that worked better.  Another problem with the tool was that the nails were pushing back out of the back of the board, so I mixed up a bit of polyester resin and glued the nails in with it.  After that it was just a matter of using a 6 inch square took and slowly poking holes in all that foam.  Did I mention it takes a while?

The new 6 inch square foam hole poking device.

Once the holes were poked, the next step was to position the foam on the frame and tie it down with some fishing line so it would retain the curve.  It needed to be positioned over a stringer so we could tackle the next step, joining the small piece of foam to the end of the large one.  With some fiddling, we got the large piece positioned and figured that we could use some light sandbags covered in plastic to hold the smaller piece in position.  I mixed up some resin, thickened with fumed silica and a little chopped glass fiber (in my spare time I've taken some of the small pieces of clean scrap cloth that were cut away from the test piece and cut the fibers into 1/4 inch or so strands), and we glued the two pieces together.  After a little curing time, we had a 4 foot by 9.5 foot slightly curved panel.

Hand sanding the curve at the top back edge.

After that, the panel had to be re positioned to it's final location on the mold and re-secured to the frame. Then the rear edge needed to be shaped so the fiberglass would curve over the edge of the foam and continue down the back of the 60 degree angle that makes up the mounting surface.  Since it is a compound curve I hand-carved the foam with a razor knife and then hand-sanded it into the correct contour.  Another labor intensive and time consuming process, but it did turn out well.

There was much debate about how we were going to fiberglass the middle of a 9 foot by 12 foot panel. We decided that we would start by putting a band of fiberglass down the middle section before we attached the side panels.  This way we can be up close and inspect the initial layer's bonding between the glass and the foam.  So, the next step was to actually lay up some glass.

Naturally, the...ahem...cooler dry days we had the last weekend were no longer in sight.  Now it is supposed to be nearing 100 degrees Fahrenheit with chances of rain in the afternoon.  Not exactly the best conditions for doing fiberglass work.  We got up yesterday ready to do some fiberglass before it got hot, we just needed to run to the store to pick up a couple of last minute things.  By the time we got back to the yard the temperature was soaring over 95 degrees. Too late to get it done until it cools off in the evening.  So, we did some other things in preparation for later steps like punching more holes in more foam panels. And we bought a work light. Remember how I lamented doing fiberglass work in the dark? Well, it seems like that might be the only time conditions are favorable for doing the layup.

It finally got back down to around 90 F after 5 P.M. and we were able to start work.  With the panel in place, I started by putting a strip of glass along the frame that will become the mounting flange along the arch of the boat.  I had previously laminated that surface of the mold with cellophane tape and sprayed it with PVA so it wouldn't stick. I coated that with some thickened resin, let that get tacky and then applied a little more regular resin and the glass.  Applying resin on a surface that is 30 degrees past vertical is a real pain in the butt.  I think I ended up wearing about as much as the fiberglass mat was.  But I was able to get it laid up with a little work.

Yep, doing fiberglass at night again.

Before the strip we applied had cured, we applied the first layer over the back part of the arch.  This was a square of the mat that was 52 inches long and 46 inches wide. It was applied to the top rear of the the foam sheet and wrapped around to the mounting flange at the back.  This left the sides of the foam clear so we can easily bond the next sheets of foam without any interference from the fiberglass mat.  Of course it was getting dark at that point, but we were a bit more prepared than just a hand-held flashlight.  This time we had a 500 watt worklight and a LED clip light to help light the work space. By the time we got that piece done, it was getting late. We packed everything up and headed back to the boat...getting there about 10 P.M.

The next morning we awoke to a good coat of dew on the inside of the work canopy.  Since I didn't like the idea of it potentially raining on me while working, we setup a fan and waited for the canopy to dry.  It did...finally...around 10 A.M. or so.  The same time it was approaching the 90 F temperature mark again.  But we did lay up the two final pieces of glass to complete the covering of the center panel of the top.  And it wasn't even dark yet.

The top of the center section with the first layer of glass.

Feeling like we might get more accomplished today, we stopped for a late lunch and were rushed back to the tent with the sound of thunder.  We get back and start buttoning things up and as we are getting things closed, the downpour starts.  And it pours.  Trying to tie things up, I'm getting soaked and the panel does get a little wet.  We quickly dry it off (the glass had cured by that point, so blotting up with towels did seem to work) and my wife re-positioned a tarp to block the rain.  Hopefully it won't cause any issues with the surface of the laminating resin so we can continue the layup when the weather improves.

It feels good to finally see something that resembles a top starting to form.


  1. Hi Mike,
    Looks good, doing the hard to reach center of top before adding the side panels certainly made it easier to reach and roll/wet the glass with resin. Glassing 90+ degree heat is no fun and the resin pot life must be short. Interesting that the 30 degree angle tab at rear is just glass right now- assume you'll be adding foam underneath for structural strength. Will the rest of the glass cloth be laid full length or width as that would seem to give you the greatest strength? Are you using the same cloth/mat combo for all layers or are you switching to just cloth after first layers. Other crusiers considering a hardtop may be interested. You seemed to have worked out the DIY kinks and your spouse seems as dedicated to getting this done, given you both worked to 10 pm.
    Doug from VT

    1. Hey Doug,

      Yeah, doing a strip down the center made it easier to make sure we had a good bond with the foam...that was the reason for doing it. We will probably continue with longer rolls of the glass, particularly if we can find a cooler time to do it. The pot life is short so you can't just do a whole 9 foot length at one time and we practiced a running layup technique as we went even though we were using shorter pieces in this section (mostly to avoid as much scrap as anything). We are going to be using mostly the same cloth. The mat does a good job of binding with the layer below and is thin enough it doesn't bulk up the overall layup too much. As for the mounting flange, it will be solid fiberglass except for the fillet that will have a foam wedge cut to reduce the amount of resin used to round the corner. I plan on writing up more of the details once I complete the project...I'm still "figuring out" things as we go here. :)